Nonwoven flexible composites

ABSTRACT

Embodiments of the present invention provide systems and methods for using nonwoven materials for evacuation slides, life rafts, life vests, and other life-saving inflatable devices. The nonwoven materials have a substrate layer with continuous filaments formed in various directions.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. Ser. No. 15/354,123 filedNov. 17, 2016 titled “Nonwoven Flexible Composites,” which applicationis a continuation of U.S. Ser. No. 15/285,738 filed Oct. 5, 2016 titled“Nonwoven Flexible Composites,” which application is acontinuation-in-part of U.S. Ser. No. 15/058,688 filed Mar. 2, 2016titled “Nonwoven Flexible Composites,” which application claims thebenefit of U.S. Provisional Application Ser. No. 62/126,898, filed Mar.2, 2015, titled “Nonwoven Airholding Fabrics,” the entire contents ofwhich are hereby incorporated by reference.

FIELD OF THE DISCLOSURE

Embodiments of the present disclosure relate generally to nonwovenflexible composites that find particular use in connection withevacuation slides, rafts, life vests, or other emergency flotationdevices. Such devices are typically formed from woven substrates, butthe present inventors have determined that using nonwoven substrates inconnection with such devices can provide improved benefits.

BACKGROUND

Federal aviation safety regulations require aircraft to provideevacuation and other safety provisions for passengers. These includeevacuation slides, life rafts, life vests, and other life-savinginflatable devices. For example, inflatable escape slides and life raftsare generally built from an assembly of inflatable tubular structuresthat form airbeams that are sealed to one another. Inflatable escapeslides and life rafts also have non-airholding features, such aspatches, floors, sliding surfaces, girts, handles, and other features. Abalance between strength and weight must be reached during the designprocess. The material must be appropriately flame resistant, haveappropriate friction to allow passenger sliding, have sufficientstrength to withstand high inflation forces, resist tearing andabrasion, but also be light enough so as to not unduly add to aircraftweight.

Evacuation slides, life rafts, life vests, or other life-savinginflatable devices and their accompanying accessories and components areinflatables typically formed from woven base substrates. A woven basesubstrate is typically coated and/or laminated in order to give it thedesired air holding characteristics. As background, woven fabricconstructions are characterized by two sets of yarns: warp and weftyarns. Warp yarns are raised and lowered to make “sheds,” and weft yarnsare passed through these sheds, perpendicular to the warp yarns (and maybe referred to as fill or pick yarns). The woven substrates givestrength and rigidity for inflatable tubular structures.

However, such a woven architecture introduces a “crimp effect” orundulations in the yarns as they pass alternately over and under oneanother during the weaving process. Yarn “crimp” is the waviness of warpyarns and weft yarn interlacing together to produce the fabricconstruction. It is affected by yarn count, fabric structure, andweaving tensions related to the strength of the textile fabric. If aload is applied on a woven fabric and the yarns are not crimped, thefull load will be faced in tension at complete strength. However, if theyarns are bent or crimped, the initial load will be consumed instraightening the bent yarns, and then take upload. The use of wovenconstruction can thus lead to “low strength materials.” The crimp effectcan also influence fiber volume fraction, which eventually leads tocompromised mechanical performance of this fabric. Specific featuresthat may be compromised are tensile and compressive properties.

When woven fabrics are used for inflatable structures, and particularlywhen used to create inflatable tubular structures that are cylindricalin shape, the inflatable structure experiences load in three directions.First, there is a circumferential stress or hoop stress, which is anormal stress in the tangential direction. Second, there is an axialstress, a normal stress parallel to the axis of cylindrical symmetry.Third, there is a radial stress, a stress in directions coplanar with,but perpendicular to, the symmetry axis. Thin sections of inflatablefabric will generally have negligible radial stress. However, the hoopstress is generally two times the axial/longitudinal stress. Thepractical effect of this is that an inflatable tube, such as anevacuation slide or life raft tube, experiences two times more stress inthe hoop direction compared to the length direction. Examples of thesetwo stresses and how they are experienced along a tubular structure isillustrated by FIG. 3. However, current woven substrates used forinflatable tubular structures are constructed with yarns having the sameor similar strength in both the hoop and the axial/longitudinaldirection. This can add to unnecessary and undesirable weight to theoverall structure.

Another challenge that can be presented by the use of woven substratesoccurs during coating of the substrates. Empty voids 10 in between theyarns 12 can create high and low points that pose challenges during thecoating process. This is generally referred to as the peak-valleyeffect, and is illustrated by FIG. 1. In order to make these fabrics“air holding” or having “gas barrier” properties, multiple layers ofcoatings 14 are put on top of one another until the desirablethicknesses are achieved. A final top coating 16 may be applied forrendering air holding features. These multiple layers of coatings 14 areundesirable, as it increases weight and cost of such fabrics.Improvements to fabrics used for inflatables are thus desirable.

Nonwoven fabric is a material made from fibers that are bonded togetherby chemical, mechanical, heat or solvent treatment. The term isgenerally used in the textile manufacturing industry to refer tofabric-like materials that are neither woven nor knitted. The use ofnonwoven materials has generally been limited to the medical industry(for surgical gowns and drapes), the filter industry (for various typesof filtration, including coffee and tea bags, vacuum bags, and soforth), the geotextile industry (for foundation stabilizers, erosioncontrol materials, sand and landfill liners), and other miscellaneousindustries (such as for carpet backing, for diapers or feminine hygieneproducts, cleaning wipes, for marine sails, for parachutes, forbackpacks or as batting in quilts or comforters). Nonwoven materialshave not, however, been used in connection with inflatable life-savingdevices as described herein. Use of nonwoven materials for these usespresents unique challenges that the present inventors have solved.

BRIEF SUMMARY

Embodiments of the invention described herein thus provide systems andmethods for using nonwoven materials for evacuation slides, life rafts,life vests, and other life-saving inflatable devices. The nonwovenmaterials described may also be used for non-airholding accessories orcomponents of these devices, such as sliding surfaces of an evacuationslide, girts, handles, raft floors, patches, or any other feature. Forinstance, in other examples, there may be provided a non-airholdingfeature on an evacuation slide, life raft, life vest or otherlife-saving inflatable device, the non-airholding feature comprising: aflexible composite material, comprising a substrate of nonwoven materialcomprising a plurality of filaments; an adhesive or primer to bind thefilaments; and a coating or film or both on one or both surfaces of thesubstrate of nonwoven material; wherein the flexible composite materialis a high-strength lightweight material with a tensile strength of atleast about 100 pounds per inch and a weight of about 8 ounces persquare yard or less, wherein the flexible composite material is adheredto the emergency device.

The nonwoven materials have a substrate layer with filaments laid downin various directions. The substrate layer is then coated and/or appliedon one or both sides as a coating or film. A coating may be in a liquidform and applied to the material. The coating may be any of theadhesives, primers, resins, or other materials described herein. Thefilm may be a layer or solid (non-liquid) sheet that is applied to thematerial. A film may be provided over a coating in some instances. Thecoating or film or both a coating and a film together may becollectively referred to herein as a “layer.” The layer may be appliedin order to render the material as having air-holding characteristics,such that it provides a gas barrier for the material. In other examples,the layer may be applied to give the material a certain finish or feel,such as a slick sliding surface, a rough life raft floor, or any otherdesired feature or finish such as improving seam adhesion or abrasionresistance. The layer can provide protection against abrasion and alsogives higher adhesion. In one example, the layer is a polymer. In oneexample, the layer may be polyurethane. In other examples, the layer maybe polyethylene, polypropylene, polyamide, polyethylene terephthalate(PET), polystyrene, ethylene vinyl acetate (EVOH), polyvinylidenechloride (PVDC), polycarbonate (PC), polyvinyl chloride (PVC), or anycombination thereof. Other potential layers that form a layer arepossible and considered within the scope of this disclosure.

Adhesives or primers may be particularly useful in cross-linking thematerials/filaments to one another. This may result in high filament toadhesive adhesion, high filament to filament adhesion, high adhesive tocoating adhesion, high adhesive to lamination film adhesion, highfilament to coating adhesion, high filament to lamination film adhesion,or combinations thereof. Exemplary adhesives or primers include but arenot limited to crosslinked polyurethanes that are solvent based or waterbased. Other polymers that can be used as primers are listed above.

In one example, there is provide an inflatable evacuation slide, liferaft, life vest, or other life-saving inflatable device, comprising: aflexible composite material, comprising a substrate of nonwoven materialcomprising a plurality of filaments; an adhesive or primer to bind thefilaments; and a layer of a gas barrier polymer on one or both surfacesof the substrate of nonwoven material; wherein the flexible compositematerial is a high-strength lightweight material with a tensile strengthof at least about 100 pounds per inch and a weight of about 8 ounces persquare yard or less, wherein the flexible composite material is adheredto itself to form a tubular structure or is adhered to another material.

In some examples, the substrate of nonwoven material comprises multiplelayers. The gas barrier polymer can be a coating or a film or both. Thespecific gas barrier polymer used may be polyurethane, polyethylene,polypropylene, polyamide, polyethylene terephthalate (PET), polystyrene,ethylene vinyl acetate (EVOH), polyvinylidene chloride (PVDC),polycarbonate (PC), polyvinyl chloride (PVC), or any combinationthereof. The gas barrier polymer layer can have a thickness betweenabout 0.5 mil to about 2 mil.

In some examples, the substrate of nonwoven material comprises anon-inflatable part of the device. For example, it may form floormaterial of a life raft or an evacuation slide, a girt material of anevacuation slide, or a handle or accessory patch of a life raft orevacuation slide.

The filaments of the nonwoven material may be non-continuous orcontinuous in length. The filaments of the nonwoven material may beunidirectional or multidirectional. They may be in a random orientationfilament layout or other random orientation. They may be one or moresingle strands positioned according to load exhibited on the structure.There may be one or more additional strands positioned on top of the oneor more single strands. The substrate of nonwoven material may be acustomized fabric comprising filaments laid in particular directions ofthe expected stress to be experienced by the device to be manufactured.The device may be a tubular structure comprising a hoop direction and alongitudinal direction, wherein there are more filaments in the hoopdirection than in the longitudinal direction. If the device has one ormore miter seam locations, there can be more filaments at the miter seamlocation than at other areas of the device. The device can includetubular structures of varying diameters, wherein structures comprisinglarger diameters comprise more nonwoven filaments than structurescomprising smaller diameters.

Examples also relate to a method for manufacturing an inflatableevacuation slide, raft, life vest, or other life-saving inflatabledevice, comprising: providing or obtaining a flexible compositematerial, comprising a substrate of nonwoven material; applying a firstlayer on at least one surface of the substrate of nonwoven material;forming the material into a tubular structure; and applying a floor orother accessory to the tubular structure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a side schematic view of a woven prior art material.

FIG. 2A shows a side schematic view of a nonwoven material, havingfilaments embedded in an adhesive matrix coated with a layer on bothsides.

FIG. 2B shows a side schematic view of a nonwoven material, havingfilaments embedded in an adhesive matrix and laminated with a layer onboth sides.

FIG. 3 shows a side schematic view illustrating various stressesexperienced by an inflatable tubular element.

FIG. 4 shows a side schematic view of one potential filament placementalong a tubular element.

FIG. 5 shows a schematic view of potential filament placement along amiter seam.

FIG. 6 shows a schematic view of a potential filament placement along atapered tubular structure.

FIG. 7A shows filaments laid at a 0° angle. FIG. 7B shows filaments laidat a 90° angle. FIG. 7C shows filaments laid at a 0° and 90° angle. FIG.7D shows filaments laid at a 45° angle. FIG. 7E shows filaments laid ata 30° angle. FIG. 7F shows filaments overlaid at a 0°, 90°, 30°, and 45°angle.

FIG. 8 shows filaments laid at random orientations.

FIG. 9 shows a single strand filament positioned in differentorientations, according to load/force.

FIG. 10 shows multiple strand filaments positioned according toanticipated high force directions.

FIG. 11 shows an example of continuous filaments laid on a substrate.

FIG. 12 shows an example of discontinuous filaments laid on a substrate.

FIG. 13 shows an example of discontinuous random filaments laid on asubstrate.

FIG. 14 shows one example of an evacuation slide that may bemanufactured using the nonwoven materials described herein.

DETAILED DESCRIPTION

Embodiments of the present invention provide substrates of flexiblecomposite materials 20 that have minimal to zero “crimp effect.” Thismay generally be referred to as “low crimp,” and this term is used torefer to materials that do not have fibers or filaments that are woundor otherwise woven together. The materials may find particular use inconnection with life-saving inflatable devices, but their uses are notintended to be limiting thereto. Examples include evacuation slides,life rafts, life-saving vests, inflatable shelters, or combinationsthereof. The materials described may be used to form air-holdingportions of these devices, but they may also be used to form otherportions of the devices, such as the floor of a life raft, floor of anevacuation slide, girt of an evacuation slide, handle of an evacuationslide, and so forth.

Straight, non (or low)-crimp filaments and/or yarns exhibit full load intension at complete strength. A flat, non-woven fabric 20 made ofstraight filaments 22 laid in certain orientations can present a flatsurface without the above described peak-valley effect, experienced bywoven fabrics. It has been found that flat surfaces can also benonporous, at least to a certain degree. This can lead to a thinnerlayer required. (This is generally because with a woven fabric, thecoating 14 needs to fill the holes created by peaks and valleys. asshown by FIG. 1. With a flat, nonwoven fabric 20, as illustrated by FIG.2, these peaks and valleys are not present.)

FIG. 2A shows straight laid filaments 22 in an adhesive 24. Thisconfiguration also has a first layer 26 and a second layer 28 on eitherside of the nonwoven substrate. FIG. 2B shows straight laid filaments 22in an adhesive 24. This configuration also has a coating or film or bothlayer 26 and a coating or film or both layer 28 on either side of thenonwoven substrate. More detail about the particular materials that maybe used are provided further herein.

Additionally, nonwoven substrates can be stronger than traditionallyused woven substrates. This can similarly lead to a thinner layerrequired to make such substrates air-holding. The present inventors havefound that the examples described herein can use about 50% lessmaterial, which can lead to a finished material that is consequentlyabout 50% lighter. Utilizing nonwoven flat substrates can thus reducethe layer weight significantly as compared to woven substrates. In fact,in some examples, minimal to no layer may be required.

Although the embodiments described herein focus on life savinginflatables, such as evacuation slides, evacuation slide/rafts, liferafts, emergency floats, emergency flotation systems, and lifepreservers, it should be understood that the disclosure is equallyapplicable to other fabric-like devices, including but not limited toinflatable/non-inflatable decontamination shelters,inflatable/non-inflatable shelters, inflatable/non-inflatable militaryshelters, ship decoys, inflatable military targets, and space inflatableapplications.

The nonwoven materials used in this disclosure may include any number ofmaterials. Examples include staple fibers or filaments, which mayinclude cotton or other natural materials. Other examples includefilament fibers, which include synthetic materials. One type of nonwovenmaterial that may be used in connection with this disclosure is anonwoven material that is a laminated mix of carbon and polymerfilaments. In one example, the material is a reinforced laminate formedfrom one or more unidirectional-tapes (also called uni-tapes) laminatedto a polymer film. The filament or monofilament material may be carbonand extended chain polyethylene or liquid crystal polymers embedded in apolymer matrix. The material may be an inorganic silicon. The materialmay be a monofilament aramid. The material may be nylon. The materialmay be polyester. The material may be cotton. The material may be ultrahigh molecular weight polyethylene (UHMWPE) filaments. The material mayincorporate boron and/or ceramics. The material may be a material thathas typically been used for sailcloth and/or for kites. The material maybe combinations of any of the above options. Additional examples aredescribed by U.S. Pat. No. 5,333,568, all of which are considered usableherein. Other materials are possible and considered within the scope ofthis application. The type of filaments used may be optimized dependingupon the particular device to be manufactured. In some examples, thefilaments used may have diameters of up to about five times less thanconventional strands or threads used for woven materials. Additionally,because of the added strength possible due to configurations of thisdisclosure, the nonwoven fabric may be about ⅓ of the thickness of atraditional woven fabric used for inflatables.

Because the final materials described herein are designed for use inconnection with inflatable structures that must withstand high inflationpressures, the materials used must be designed to withstand suchpressures. As background, current slide, life raft, and life vestfabrics must meet FAA requirements listed under appropriate technicalstandard order (TSO). The TSO prescribes the minimum performancestandards (MPS) that these emergency evacuation products must meet.Current woven inflatable air-holding fabrics have average finishedfabric weights of approximately 8.0 oz/sq yard. (A typical breakdown isthat 50% (4.0 oz/sq yard) is the substrate weight and 50% (4.0 oz/sqyard) is the coating and/or lamination film weight.) These inflatablefabrics must also meet a minimum tensile strength of 190 lbs/inch (forslides and life rafts) and 210 lbs/inch (for life vests). These arecurrent requirements set by regulatory authorities, such as the FAA.However, it is believed that the present concepts may also find use onmaterials that have a tensile strength of 100 lbs/inch, 120 lbs/inch,130 lbs/inch, 140 lbs/inch, 150 lbs/inch, 160 lbs/inch, 170 lbs/inch,180 lbs/inch, or any integers there between.

Typically, many pieces of fabric (panels) are joined together to formtubular structures. The strength requirement is thus not limited only tothe body fabric (the field of the inflatable tube), but is also requiredon seam areas. In order to keep the gas inside the tubes for longdurations, the seams must be sealed together (via thermal welding oradhesive bonding methods) to make them leak proof. Such seams must meetminimum shear strengths of 175 lbs/inch (at room temperature) and 40lbs/inch (at elevated temperature of 140° F.). Such seams must have apeel strength of 5 lbs/inch (slides and life rafts) and 10 lbs/inch(life vests). The requirements outlined herein are current requirements;it should be understood that the materials described by this disclosuremay have various features modified in order to meet other requirementsthat may be set in the future or by different regulatory authorities.Safety product inflatables also need to comply with a high pressure test(also called overpressure test) requirement, in which the device mustwithstand high inflation pressures without causing any damage to theintegrity of the seams. For example, slides are required to withstandtwo times the maximum operating pressure without failure for at leastone minute. Depending upon the tube diameter and maximum operatingpressure established for that slide, the hoop stress/load/force (whichis the larger of the two stresses experienced by the seams) can vary.For example; a 24″ diameter tube with 3.5 psi maximum operating pressurewould experience hoop stress of about 84 lbs/inch.

As discussed above, existing nonwoven fabrics available on the marketand described by prior art literature are primarily used for low costcommodity items, such as filters, hospital gowns, hygiene products, andso forth. These fabrics are low cost materials, where the necessary andachieved strength is nowhere near the strength required on inflatableproducts for safety applications, which experience large pressure loads.Existing inflatable nonwoven materials do not meet any of theabove-listed TSO strength requirements at desirable weights. This meansthat in order to reach the desired strength, the materials would need tobe so heavy that they would be unworkable for being stored on board avehicle where reduced weight is a major concern. By contrast, at thedesired low weights, currently-available nonwoven materials would nothave the required strength. Accordingly, the present inventors havespecified nonwoven materials having strengths that allow them to be usedin the safety inflatable applications described herein, while alsohaving the desired low weights.

The nonwoven substrates used are thus highly engineered nonwovensubstrates made with specialized engineered filaments and polymericlayers to achieve the highest strength to weight ratio on inflatableair-holding fabrics for life-saving inflatable devices. In specificexamples, the materials achieve a fabric tensile strength of up to ormore than about 190 lbs/inch for slides and life rafts and about 210lbs/inch for life vests. In other examples, the materials achieve afabric tensile strength of up to about 100 lbs/inch. In other examples,the materials achieve a fabric tensile strength of up to about 120lbs/inch. In other examples, the materials achieve a fabric tensilestrength of up to about 130 lbs/inch. In other examples, the materialsachieve a fabric tensile strength of up to about 140 lbs/inch. In otherexamples, the materials achieve a fabric tensile strength of up to about150 lbs/inch. In other examples, the materials achieve a fabric tensilestrength of up to about 160 lbs/inch. In other examples, the materialsachieve a fabric tensile strength of up to about 170 lbs/inch. In otherexamples, the materials achieve a fabric tensile strength of up to about180 lbs/inch. In specific examples, the materials achieve a shearstrength of up to or more than about 175 lbs/inch (at room temperature)and 40 lbs/inch (at 140° F.). In specific examples, the materialsachieve a seam peel strength of up to or more than about 5 lbs/inch(slides and life rafts) and 10 lbs/inch (life vests). In specificexamples, the materials can withstand TSO overpressure requirements of 2times the maximum operating pressure.

Even when nonwoven materials are used for air mattresses, the materialsare not manufactured or designed to withstand the type of inflationpressures described herein. The focus of those materials is to be lowcost. Accordingly, nonwoven air mattress materials are generally made ofshort random fibers that do not have a high strength. Using inflationpressures required by aircraft regulations on camping air mattresseswould cause the low cost air mattresses to split. For perspective, theseair mattresses have a tensile strength of about 100 pounds per inch orless, a weight of about 16 ounces per square yard or greater, and aburst strength of less than about 5 psi. They are also not designed towork in extreme temperature conditions (such as −40° F. up to 160° F.).

Exemplary test data provides that in contrast to the current state ofthe woven coated fabrics, which have low strengths and high weights,using the technologies described herein, it is possible to provide aninflatable structure with a strength to weight ratio of about190/4=47.5. By contrast, woven composites generally have a strength toweight ratio (minimum) of about 190/8=23.75. Other nonwoven strength toweight examples include but are not limited to 190/7, 190/6, 190/5,190/4, 190/3 and 190/2 or any permutations of fractions thereof. (Theseexamples provide a tensile strength of 190 pounds per inch and weightsof about 2 to about 7 ounces per square yard.)

In addition to laying down filaments on an adhesive substrate or apaper, it is also possible to manufacture the flexible nonwovencomposite as a web using other technologies. The nonwoven materialsdescribed may be manufactured in any number of ways. They may bemanufactured using mechanical means, heat means, water means, orcombinations thereof. Some specific examples of ways that the non-wovensused in this disclosure and accompanying claims may be manufacturedinclude, but are not limited to, felting, adhesive bonding, spin laying,carding, spun bonding, wet-laid filaments, stitching or stitch bonding,needling or needle punching, calendaring, hydro entanglement using highjet pressures, and/or hot air bonding or thermal bonding. The filamentsof fibers may be manufactured by spun bonding, wet bonding, dry bonding,or any other appropriate methods.

As illustrated by FIG. 2A, the monofilaments 22 can be uniformlyembedded in an adhesive matrix using an elastomeric polymer matrix orbonding adhesive 24. In other examples, the filaments can be pre-coatedto become “sticky filaments” that can be laid on a paper substrate. Thepaper can be peeled away, and the resulting filament can be sandwichedby layers of a polymer film. Laying down filaments in this way, asopposed to weaving the filaments, can help address the above-describedproblems created by woven products. Instead, this solution provides aflat substrate. The substrates may form a reinforcing material that ispositioned between upper and lower layers of a polymer layer. Asdescribed in more detail below, it is possible to lay down filaments invarying configurations in order to provide an engineered filamentplacement for the desired use. The filaments may be continuous ornon-continuous filaments or any combination thereof. The filaments mayall have the same diameter or filaments of varying diameters may beused. The layer of monofilaments can be a single layer or multiplelayers.

When nonwoven materials are used for sailcloth and kites, the polymerfilm of the above-described configuration used is generally Mylar. Thefilaments are laid down into a resin and a top and bottom layer of Mylaris positioned on either side of the filaments. The material isautoclaved so that heat and pressure can fuse and cure individualcomponents together.

The present inventors have found, however, that the use of Mylar as thepolymer film is not optimal for securing to or otherwise working withthe adhesives used to manufacture life-saving inflatable devices. Mylarbeing a low surface energy substrate, does not adhere well to filaments,coatings and/or films even when assisted with cross-linking adhesives,thereby causing delamination and peeling of the filaments from thecoating and/or film when put under the prescribed load of an inflatablesafety product. Instead, the materials of the present disclosure use apolyurethane layer 26, 28 on one or both sides of the nonwoven basesubstrate/structure. Other examples of layers include but are notlimited to polyvinylidene chloride (PVDC), polyvinyl alcohol (PVOH),ethylene vinyl alcohol (EVOH), Polyethylene Terephthalate (PET),Polyethylene (PE), Polyamides, Polypropylene (PP), Polylactic acid(PLA), or any other appropriate polymer, or combinations thereof. FIGS.2A and 2B provide schematics illustrating a configuration with a layeron both sides of the substrate. It should be understood that it is alsopossible for the layer to be applied to only a single side or surface ofthe substrate. It was unexpectedly found that by replacing the Mylarfilm with a polyurethane (or other) layer, the nonwoven materialfunctions optimally for the life-saving inflatable devices describedherein.

Polyurethanes are formed by the reaction of two components: anisocyanate component and a polyol component. Polyurethanes are generallyhigh molecular weight polymers with a broad range of properties due to awide range of formulation variables. Exemplary variations and types ofpolyurethane that may be used in connection with this disclosureinclude, but are not limited to:

aromatic or aliphatic polyurethanes;

thermoplastic polyurethanes (TPU) (thermoplastic urethanes are polymersthat can be melted and reformed; they are elastic and highly flexible)thermoset based polyurethanes (a thermoset urethane is a polymer thatcannot be melted and reformed and is generally more durable thanthermoplastic urethanes);

polyester TPUs, which have high resistance to oils and chemicals andprovide excellent abrasion resistance;

polyether TPUs, which are slightly lower in specific gravity thanpolyester and polycaprolactone grades and offer low temperatureflexibility, good abrasion and tear resilience, are durable againstmicrobial attack, and provide good hydrolysis resistance, making themsuitable for applications where water is a consideration; and

polycaprolactone TPUs, which have the inherent toughness and resistanceof polyester-based TPUs combined with low-temperature performance and arelatively high resistance to hydrolysis.

Additionally, the adhesives/resins, coatings and films that are to beused on the nonwoven flexible composites described herein need not belimited to polyurethane material. Other exemplary polymeric layers thatcan be used in place or in conjunction with polyurethanes include, butare not limited to, polyvinylidene chloride (PVDC), polyvinyl alcohol(PVOH), ethylene vinyl alcohol (EVOH), Polyethylene Terephthalate (PET),Polyethylene (PE), Polyamides, Polypropylene (PP), Polylactic acid(PLA), or any other appropriate polymer, or combinations thereof.

In one example, the layer may have a thickness of about 0.5 mil to about5 mil. In another example, the layer may have a thickness of about 0.5mil to about 2 mil. In another example, the polyurethane layer may havea thickness of about 1 mil.

It is also possible to apply adhesive on the filaments duringmanufacture, in addition to their being mounted on a film. This mayassist further with adhesion of the material to itself or to othermaterial portions for manufacture of the desired shapes.

Additionally, the adhesives used by the present assignee are believed tobond with the polyurethane layer in order to cause the material tobecome an integral, one-piece, or otherwise monolithic, singleconstruction of material that is cross-linked and that will notdelaminate from itself. One exemplary adhesive that has found success isan isocyanate-based adhesive. Other adhesives that may be used include,but are not limited to, those listed above.

If the filaments are additionally coated with an adhesive (in additionto or instead of a polyurethane or other adhesive), this may furtherhelp the bonding/cross-linking described. For example, using anisocyanate-based adhesive with a polyurethane film that is coated orlaminated onto the filament substrate can provide a strengthenedmaterial specifically designed for high stress uses. Theisocyanate-based adhesive may be added during formation of thesubstrate; isocyanate-based adhesive may be used as an adhesive on theoutside of the material; and/or an isocyanate-based adhesive primer maybe used. If the material is welded and a specific adhesive is not used,it is possible to incorporate isocyanate-based adhesive during theformation of substrate adhesive and/or apply an isocyanate-basedadhesive primer on the seams to be welded.

Filament orientations can play a significant role in determiningtensile, tear, and puncture properties of fabrics. In one example, it ispossible to provide areas of the material that are loaded with morefilaments than at other areas of the material. Embodiments of thisdisclosure provide varying filament orientations that can includedifferent filament thicknesses and/or filament densities at miteredjoints or seams, at diameter changes (tapering of fabrics) and/or athoop stress versus length locations.

For example, referring now to the orientation of the flexible compositespanels/substrates formed for evacuation slides, a relatively high loadis generated by the air pressure used to inflate the tubes that form theairbeams. Alternatively, high pressures are also experienced by liferaft floors, evacuation sliding surfaces, handles, and other accessoriesor non-airholding features on the devices. These high loads also need tobe maintained in order to preserve structural rigidity under the weightof the slide and under the weight of passengers during use. The loadsacross the diameter of a tube (in the hoop direction 32) are generallylarger than the loads in the length or longitudinal direction 34 of thetube. This is illustrated schematically by FIG. 3. Because the tubesthat form the air beams on an evacuation slide do not experiencebalanced loads, it is possible to design the fabric to be manufacturedto be stronger in one direction as opposed to another direction.Accordingly, various engineered filament orientations are also describedherein. The engineered filament orientations may provide enhancedstrength at certain areas where the inflatable lifesaving structurestypically experience high stresses. For example, it may be possible toprovide more filaments or reinforced filament areas on the tube wherehigher stresses will be experienced. These filaments may be in the sameor different directions.

For example, as illustrated by FIG. 4, it is possible to provide twotimes as many filaments 22 in the hoop direction 32 as in theaxial/longitudinal direction 34. In other examples, it is possible toprovide 1.5 times as many filaments, three times as many filaments, fourtimes as many filaments, or any other desired strength parameters.

In the example shown by FIG. 5, it is possible to bunch or stack morefilaments at miters or joint locations 36. In the example shown by FIG.6, it is possible to design larger diameter tubes that are loaded withmore filaments. In this example, there is a tapered section 38 of anevacuation slide that is loaded with more filaments at the largerdiameter portion 40. These options allow the filament orientations to bevaried and customized so that they are strongest in the desiredlocations, while still maintaining the lightest possible material atother locations.

Additionally, when nonwoven materials are used for sailcloth and kites,the filaments used are unidirectional filaments. Even if multiplesubstrate layers are used in order to provide filaments of differentdirections, each substrate itself has filaments that are in the samedirection. By contrast, the present inventors have determined thatlaying multiple directions of filaments on a single panel can addstrength to the resulting product.

For example, each panel can be customized with the particular filamentorientations desired. They may be unidirectional or multidirectional orany combination thereof. For a woven cloth, filaments are always at a90° angle with respect to one another. FIG. 7A illustrates filaments at0° angle. FIG. 7B illustrates filaments at 90° angle. FIG. 7Cillustrates filaments overlaid or interwoven at 0° and 90° angles. Thisis the only possible result of a woven material. However, with anonwoven material, other combinations are possible. The filaments may beoriented at 0°, 25°, 30°, 45°, 60°, 90°, or any desired angle. Thefilaments may be laid in any orientation desired. Just a few examplesare illustrated by FIGS. 7D-F. FIG. 7D illustrates filaments at 45°angle. FIG. 7E illustrates filaments at 30° angle. FIG. 7F illustrates acombination of filament substrates overlaid on one another, providing amaterial having a combination of angled filaments. In this example,angles of 0°, 90°, 30°, and 45° are illustrated, but it should beunderstood that other combinations are possible and considered withinthe scope of this disclosure.

In addition to providing multiple filaments that may be overlaid withrespect to one another in order to provide a customized or engineeredfilament positioning/orientation, it is also possible to lay down singlecontinuous filaments at multiple angles. One example is illustrated byFIG. 8. In this example, there are three different angles of filaments22 a, 22 b, 22 c provided on a single substrate. This example may bereferred to as a random orientation filament.

In another example, it is possible to provide a single strand of afilament/yarn that is positioned according to expected load/force thatwill be exhibited on the inflatable product. In FIG. 9, there isillustrated a single strand filament 22 that is wound in a firstdirection 42, curved into a second direction 44, and then curved into athird direction 46. This is one example only. It is possible for otherdirections to be provided. It is also possible for additionalfilament(s)/yarn(s) 22 to be positioned on top of the firstfilament/yarn 22. One example of this is shown by FIG. 10. In thisexample, the filament is reinforced in the directions where the highestforce is expected.

The filaments used may be continuous fibers, as shown by FIG. 11. Thefilaments used may be discontinuous filaments, as shown by FIG. 12. Thefilaments used may be discontinuous random filaments, as shown by FIG.13.

Additionally, or alternatively, it is also possible to use multiplereinforced sheets of monofilament material between polymer layers. Inone embodiment, about two to about ten reinforced sheets oriented indifferent directions may be used as the reinforcing material between thepolymer layers. For example, two or more filament sections or substratesmay be positioned at 90° to one another in order to help provide astrengthened material. For example, a single filament section orsubstrate may have filaments running at different angles with respect toone another in order to help provide a strengthened material. Otheroptions are possible and considered within the scope of this disclosure.

FIG. 14 illustrates one example of an evacuation slide 50 that may bemade using the nonwoven materials of this disclosure. The slide 50includes a sliding surface 52, air holding tubes 54, a girt 56, handles55, and accessory patches 60. The nonwoven materials described hereinhave been directed to manufacture of the air holding tubes 54. It shouldalso be understood that the sliding surface 52 or any other surface maybe made of a similar nonwoven material. The sliding surface 52 may bebonded to an air holding tube 54 using the same or similar technology asthe way that the ends of an air holding tube 54 material would be bondedto one another. For example, an isocyanate-based adhesive may be used.In other examples, the alternate adhesives described herein may be used.In other examples, various forms of welding technologies may be used.

Changes and modifications, additions and deletions may be made to thestructures and methods recited above and shown in the drawings withoutdeparting from the scope or spirit of the disclosure or the followingclaims.

What is claimed is:
 1. An inflatable evacuation slide, life raft, life vest, or other life-saving inflatable device, comprising: a flexible composite material, comprising a substrate of nonwoven material comprising a plurality of filaments; wherein the flexible composite material is a high-strength lightweight material with a weight of about 8 ounces per square yard or less.
 2. The device of claim 1, wherein the substrate of nonwoven material comprises multiple layers.
 3. The device of claim 1, wherein the filaments are filaments that are unidirectional or multidirectional.
 4. The device of claim 1, wherein the filaments comprise a random orientation.
 5. The device of claim 1, wherein the substrate of nonwoven material comprises a customized fabric comprising filaments laid in particular directions of the expected stress to be experienced by the device to be manufactured.
 6. The device of claim 1, wherein the device comprises a tubular structure comprising a hoop direction and a longitudinal direction, wherein there are more filaments in the hoop direction than in the longitudinal direction.
 7. The device of claim 1, wherein the device comprises one or more miter seam locations, wherein there are more filaments at the miter seam location than at other areas of the device.
 8. The device of claim 1, wherein the device comprises tubular structures of varying diameters, wherein structures comprising larger diameters comprise more nonwoven filaments than structures comprising smaller diameters.
 9. The device of claim 1, wherein the plurality of filaments are formed by spun bonding, wet bonding or dry bonding.
 10. The device of claim 1, wherein the nonwoven raw material comprises staple fibers, filament fibers, or a combination thereof.
 11. The device of claim 1, wherein the nonwoven material is formed by felting, adhesive bonding, thermal bonding, stitch bonding, needle punching, hydro-entanglement, or spin laying.
 12. The device of claim 1, wherein a seam is formed via application of hot air, radio frequency, ultrasonic welding, adhesive bonding, thermal welding, or any combination thereof.
 13. The device of claim 1, wherein the substrate of nonwoven material comprises a non-inflatable part of the device.
 14. The device of claim 13, wherein the substrate of nonwoven material comprises floor material of a life raft, an evacuation slide, a girt material of an evacuation slide, or a handle or accessory patch of a life raft or evacuation slide.
 15. The device of claim 1, wherein the filaments are continuous or non-continuous in length.
 16. The device of claim 15, wherein the filaments are non-continuous filaments with a random orientation filament layout.
 17. The device of claim 1, wherein the filaments comprise one or more single strands positioned according to load exhibited on the structure.
 18. The device of claim 17, further comprising one or more additional strands positioned on top of the one or more single strands.
 19. The device of claim 1, further comprising a gas barrier layer.
 20. The device of claim 19, wherein the gas barrier layer comprises a gas barrier polymer coating.
 21. The device of claim 19, wherein the gas barrier layer comprises a gas barrier polymer film.
 22. The device of claim 19, wherein the gas barrier layer comprises polyurethane, polyethylene, polypropylene, polyamide, polyethylene terephthalate (PET), polystyrene, ethylene vinyl acetate (EVOH), polyvinylidene chloride (PVDC), polycarbonate (PC), polyvinyl chloride (PVC), or any combination thereof.
 23. The device of claim 19, wherein the gas barrier layer comprises a thickness between about 0.5 mil to about 2 mil.
 24. A non-airholding feature on an evacuation slide, life raft, life vest or other life-saving inflatable device, the non-airholding feature comprising: a flexible composite material, comprising a substrate of nonwoven material comprising a plurality of filaments; wherein the flexible composite material is a high-strength lightweight material with a weight of about 8 ounces per square yard or less.
 25. The feature of claim 24, wherein the flexible composite material is adhered to the emergency device.
 26. The feature of claim 24, wherein the non-airholding feature comprises a life raft floor, an evacuation slide surface, a girt, a handle, a patch, or an accessory.
 27. The feature of claim 24, further comprising a coating or film on one or both surfaces of the flexible composite material that comprises polyurethane, polyethylene, polypropylene, polyamide, polyethylene terephthalate (PET), polystyrene, ethylene vinyl acetate (EVOH), polyvinylidene chloride (PVDC), polycarbonate (PC), polyvinyl chloride (PVC), or any combination thereof.
 28. A method for manufacturing an inflatable evacuation slide, raft, life vest, or other life-saving inflatable device, comprising: providing or obtaining a flexible composite material of claim 24, forming the composite material of claim 24 into a tubular structure.
 29. The method of claim 28, further comprising applying a floor or other accessory to the tubular structure.
 30. The method of claim 29, wherein the floor or other accessory comprises the composite material of claim
 24. 31. A method for manufacturing an inflatable evacuation slide, raft, life vest, or other life-saving inflatable device, comprising: forming an evacuation slide, raft, life vest, or other life-saving inflatable device; and applying the composite material of claim 24 to the device as a floor or other accessory. 